(a) (i) Mention the various states of matter
(ii) Arrange the states of matter in decreasing order of:
I. kinetic energy of particles;
II. disorderliness between particles;
III. forces of cohesion between particles.
(iii) A pure sample of a substance melts at 35°C and boils at 100°C.
I. Sketch a graph to show the heating curve
II. What is the state of the substance at normal room temperature? [9 marks]
(b) Consider the following equation:

The question was attempted by most candidates and the performance was fair.
In(a)(i) and (ii), Candidates correctly mentioned solid, liquid and gas as the states of
matter and gave the arrangement of the states of matter as follows:

In part (c), most candidates correctly inferred ammonia and HCL in (i) I and II. However, most of
them could not explain their answer in (ii). In (c)(iii), most candidates correctly wrote an eqation
for the decomposition

The expected responses from candidates in each of (ii) and (iii) were as follows:

In part (d) (i), candidates named potassium trioxosulphate(IV) and sodium trioxosulphate(IV) as
the two salts that would react with dilute acids to produce sulphur(IV)oxide.
In(d)(ii), candidates mentioned two uses and one chemical property of sulphur(IV)oxide from
among the following:

- as germicide

- manufacture of tetraoxosulphate(VI) acid
- as preservative
- as refrigerant
- as bleaching agent.
II. Sulphur (IV) oxide combines with water to form solution of trioxosulphate (IV) acid
reacts with oxygen in the presence of catalyst to form sulphur(VI)oxide
reacts with alkali to form salt and water
reacts with H2S to form water
bleaching action.